816161 has 2 divisors, whose sum is σ = 816162. Its totient is φ = 816160.

The previous prime is 816157. The next prime is 816163. The reversal of 816161 is 161618.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 776161 + 40000 = 881^2 + 200^2 .

It is a cyclic number.

It is not a de Polignac number, because 816161 - 2² = 816157 is a prime.

It is a super-2 number, since 2×816161² = 1332237555842, which contains 22 as substring.

Together with 816163, it forms a pair of twin primes.

It is a Chen prime.

It is an alternating number because its digits alternate between even and odd.

It is a nialpdrome in base 16.

It is not a weakly prime, because it can be changed into another prime (816163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 408080 + 408081.

It is an arithmetic number, because the mean of its divisors is an integer number (408081).

2⁸¹⁶¹⁶¹ is an apocalyptic number.

It is an amenable number.

816161 is a deficient number, since it is larger than the sum of its proper divisors (1).

816161 is an equidigital number, since it uses as much as digits as its factorization.

816161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 288, while the sum is 23.

The square root of 816161 is about 903.4162938535. The cubic root of 816161 is about 93.4527199548.

Adding to 816161 its reverse (161618), we get a palindrome (977779).

The spelling of 816161 in words is "eight hundred sixteen thousand, one hundred sixty-one".